Ever notice that if you don't click on a Google AdWords listing and refresh your search, Google may remove the top Google AdWords listing? For example, I did a Google search on "hard drives." The first time I conducted my search, Google displayed an AdWords ad at the top, above the organic listings, with the yellow background. Here is a picture:
Notice the TigerDirect ad at the top.
Afterwards, I refreshed the search for that keyword and Google dropped the top ad and moved it to the right hand column. Notice the TigerDirect ad moved from the top position on the left and is now visible at the top right position.
Google has been doing this since September 2006, but back then it was when the top Google ads were blue. Just thought I would refresh the topic since it has come up a few times in the forums.
Forum discussion at DigitalPoint Forums.